Cytotoxic Effect of β-Amyloid on a Human Differentiated Neuron Is Not Mediated by Cytoplasmic Ca2+ Accumulation |
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Authors: | Zhi-yong Gao Heather W Collins Franz M Matschinsky Virginia M-Y Lee Bryan A Wolf |
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Institution: | Departments of Pathology and Laboratory Medicine and; Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, U.S.A. |
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Abstract: | Abstract: The effects of synthetic β-amyloid (Aβ1–42) on cell viability and cellular Ca2+ homeostasis have been studied in the human neuron-like NT2N cell, which differentiates from a teratocarcinoma cell line, NTera2/C1.D1, by retinoic acid treatment. NT2N viability was measured using morphological criteria and fluorescent live/dead staining and quantified using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide metabolism. Aβ1–42 dose-dependently caused NT2N cell death when it was present in the cell culture for 14 days but had no effect on viability when it was present for 4 days. The lowest effective concentration was 4 µ M , and the strongest effect was produced by 40 µ M . Control NT2N cells produced spontaneous cytosolic Ca2+ oscillations under basal conditions. These oscillations were inhibited dose-dependently (0.4–40 µ M ) by Aβ1–42 that was present in the cell culture for 1 or 4 days. Ca2+ wave frequency was decreased from 0.21 ± 0.02 to 0.05 ± 0.02/min, amplitude from 88 ± 8 to 13 ± 4 n M , and average Ca2+ level from 130 ± 8 to 58 ± 3 n M . The Ca2+ responses to 30 m M K+ and 100 µ M glutamate were not different between control and Aβ-treated cells. Thus, the results do not support the hypothesis that cytosolic early Ca2+ accumulation mediates Aβ-induced NT2N cell death. |
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Keywords: | β-Amyloid Cytotoxicity Neurons Cytoplasmic Ca2+ |
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